Read Why Google Wave Sucks, And Why You Will Use It Anyway. Great roundup on TechCrunch about the successes and failures of the Wave public preview. It's the only thing I've read so far that so thoroughly and thoughtfully sums up my love/hate relationship with the product so far.
And here's probably the most important advice in the piece:
Remember: don’t share confidential information in waves. As soon as you invite somebody to a wave, he can access it forever. If the discussion reveals secrets you don’t want to share with all participants, you’re out of luck: there is no way to get anybody out of the wave. The only chance you have is to create a new wave from the existing one. If you don’t want to do that, you’d better keep confidential information out.